1. Field of the Invention
The invention relates to a rigid connection device, which has at most one degree of freedom, and which connects a reference solid and a bar; and to the application of such a device to a motor cycle having a rigid frame and an engine block, the frame including a steering column.
The invention is particularly applicable to motor cycles, but it should be understood that the invention may have other applications.
The application of the invention to two-wheeled vehicles, will be described with reference solely to motor cycles, but it is understood that the invention is applicable to any two-wheeled vehicle, the term motor cycle being used here for simplicity.
The invention is applicable more particularly to high-performance motor cycles in which control of the machine requires the elimination of all low-frequency vibrations which deform elastically the structure connecting the wheels to the engine block.
2. Description of the Prior Art
In United Kingdom Patent Nos. 211,281 and 7,289(1915), motor cycle frames have already been proposed in which each of the conventional front elements is replaced by two straight, divergent tubes to the ends of which two side frames are fixed. British Patent No. 16,693(1915) proposed a structure of tubes having articulated connections.
However motor cycle frames, even those just mentioned, have insufficient torsional rigidity to avoid all risk of low-frequency resonance with variations of forces resulting from external or internal causes. External causes include defects of road surfaces and gusts of wind, while the internal causes include the behaviour of tyres, shock absorbers, and the rider himself, and also the dynamic moments of the wheels and crankshaft.
A main object of the invention is to provide a rigid structure for connecting a reference solid and a bar, and to provide a motor cycle construction in which the motor cycle engine constitutes the reference solid and the steering column constitutes the bar. A motor cycle constructed with a connecting structure according to the invention must be able to withstand more satisfactorily than known motor cycles the torsional forces of the connection between the steering column and the frame by eliminating all low-frequency vibrations effecting elastic deformation.
Another object of the invention is to provide a rigid structure which can be manufactured easily without requiring expensive experimentation or complicated calculations. Yet another object in the case of a motor cycle, is to provide better behaviour in the event of a fall.